The invention relates to a cigarette pack having an elongate blank which is made of thin packaging material, such as paper, tin foil or the like, and is intended for wrapping a cigarette group such that the blank has a continuous, single-layer base wall which is adjoined by a front wall and a rear wall, the cigarette group, which butts against the base wall by way of end surfaces of the cigarettes, being wrapped in a U-shaped manner in the process, it being the case that the base wall is adjoined laterally by base folding tabs and the front wall and rear wall are adjoined laterally by side tabs for forming folded side walls of the wrapper. The invention also relates to a process and apparatus for producing cigarette packs of the abovementioned type.
The types of cigarette pack which are most commonly known throughout the world, namely hinge-lid packs and soft-carton packs, are constructed such that the cigarette group is enclosed by an inner wrapper made of thin packaging material, namely tin foil or paper in particular. The cigarette group is wrapped so as to form a continuous base wall against which the cigarettes butt by way of end surfaces. (Narrow) Side walls and an end wall, which is located opposite the base wall, are formed by overlapping folding tabs.
In a first folding step, the blank of the inner wrapper is folded around the cigarette group in a U-shaped manner, said cigarette group being transported by a cigarette conveyor and the blank being held on standby transverse to the conveying plane as a curtain for being carried along by the cigarette group.
As the operating speed of the packaging machines increases, the problem of mechanical loading of the cigarettes becomes greater. Pressure and impact loading during the packaging process may result in the quality being impaired.
The object of the invention is to propose measures which, despite a relatively high operating speed of the packing machine, avoid, or reduce the risk of, the cigarettes being impaired.
In order to achieve this object, the cigarette pack according to the invention is characterized by the following features:
a) the base wall is separated off from the front wall and rear wall by transverse impressed lines in the region of right-angled folding edges,
b) the transverse impressed lines extend merely in the region of the base wall and front wall and rear wall, but not in the region of the side folding tabs and base folding tabs.
According to the invention, it is merely those regions of the blanks which are gripped directly by the cigarette group and/or by the cigarette ends located at the front, as seen in the conveying direction, namely the base wall, which are bounded by preformed and/or pre-impressed folding lines, with the result that, here, the mechanical loading which occurs is reduced on account of the folding of the blank. The transverse impressed lines do not extend into the lateral regions of the blank, especially since, there, another, complex folding formation is provided by base folding tabs and folding gussets.
Further pre-impressed folding lines, namely longitudinal impressed lines, are provided for separating off a central, continuous region of the blank from lateral folding tabs.
According to the invention, all the folding tabs are provided on a material web for producing the blanks, the longitudinal impressed lines being continuous impressed lines.
Further measures are provided according to the invention in the region of the packaging machine. Thus, an endless cigarette conveyor, which removes the cigarette groups from a cigarette magazine and also transports said groups when the latter receive the blank for the inner wrapper, is driven in a non-uniform manner according to the invention such that, when the cigarettes are removed from the magazine and/or when the transversely directed blank is received, the conveying speed is lower and elsewhere the conveying speed is correspondingly higher. Accordingly, the movement characteristics of the cigarette conveyor are non-uniform with acceleration characteristics running in waveform.
A further special feature of the apparatus is that assigned to the latter, preferably directly in the region where the blank is fed to the respective cigarette group, is an impressing subassembly which, before the blank has been severed from a material web, provides impressed lines in the formation according to the invention.
Further details relate to conveying elements which facilitate the transfer of the blanks to the cigarette group and the U-shaped folding.